Sorry---taking money out of a 401k to make a down payment on a house is not an exception to the early withdrawal penalty. You can take money from a traditional IRA without that 10% penalty, but not from a 401k. You will be subject to the 10% early withdrawal penalty if you were younger than 59 1/2 plus ordinary income tax on the distribution from your 401k.
To enter your retirement income, Go to Federal> Wages and Income>Retirement Plans and Social Security>IRA 401 k) Pension Plan Withdrawals to enter your 1099R.
All 401k withdrawals are subject to regular income tax.
There are some exceptions to the 10% penalty for early withdrawal if you are under age 59-1/2, but the exceptions are different for different types of plans and an IRA is not the same as a 401k in the tax law even though they have the same basic purpose.